The flap of the skirt has to be lifted to expose a large sheet of cloth printed with the red Coca Cola logo. By unfolding the sheet and stepping to the side of the street, a woman can hide behind it to misguide a would-be attacker. A deluxe version of the skirt has four sides to provide complete protection.

Tsukioka says her inspiration has been Japanese ninja assassins, who cloak themselves in black blankets so that they cannot be seen in the night.

She says the invention fits in with Japanese sensibility. "It is just easier for Japanese to hide. Making a scene would be too embarrassing."

The designer's other inventions include a manhole bag which unfolds to look like a sewer cover and a backpack which can transform into a fire hydrant to hide a child.